Attic Insulation Question

[al76slc]

Most of the stuff I see concerns how to insulate the ceiling of the attic. My attic floor is insulated but the ceiling is uninsulated. I am thinking about leaving the ceiling alone to allow air flow, but I'm wondering if I should insulate the side wall.

Attic is not living space, just storage.

Bedrooms are below the attic.

I am in NY, north of NYC. Winter temps get down to 20's typically.

Attic has typical ridge and soffit vents.

The attic is about 9 ft high at the peak. down to 1 ft at the sides.

Side wall faces east.

I already have the insulation (bought years ago), and trying to figure out what to do with it.

Any reason not to do it, or am I just wasting my time?

Thanks,
Al

[MS Fowler]

You need to consider how the heat flows out of the conditioned areas of your house. Heat rises, so, the insulation in the attic floor is what is resisting that heat flow. To be most effective, insulation needs to be placed where there is the highest temperature differential. From the unheated space above the current attic floor to the outside air, there is probably not a great temperature differential--unless you decide to heat/ condition the attic space. But if it is just an unheated attic, you will gain little from insulation that is anywhere except at the attic floor level.
You didn't give your location, but R40 might not be too much.
Yes, keep air flow thru the attic, above the insulation to prolong roofing life.

[t walgamuth]

I don't picture how the side walls fit in the picture.
1. Are they between a heated area and the outside? If not then insulating them will not do you any good.
2. Is the attic floored?
3. If so, how much insutlation is there between the flooring and the ceiling of the heated area below?
4. Do you use the attic for storage?
5. Is the whole area floored?

Any areas unfloored should have about an R-40. If your floored area has less but still has a reasonable amount of insulation you may want to leave it alone.

A typical house loses more heat through the ceiling than any of the walls but all radiant loss, if well insulated, will probably not equal the loss from windows and doors, the biggest portion being infiltration which is what comes in thruogh any cracks around the doors and windows and when you open and close the doors.

My preferred insulation is fiberglass or mineral wool. It is non toxic and the critters won't build nests in it. Also if it gets wet when it dries out it is unaffected by having been wet. I like the loose wool version best when using on in a horizontal placement.

[barry123400]

You just want 100 percent ceiling integrety on the ceiling insulation. Anything more is basically a waste in another vented location. Your attic is ventalated I hope.

Todays Canadian codes amount to about 15 inches of ceiling insulation up here in Canada. You are also far enough north that it makes sense to me as well in your location.

You may want to consider lifting the attic floor or some other solution to increase the ceiling insulation to more modern levels. Chances are the ceiling is just 2x4s. If the house is quite old perhaps a little thicker than current 2x4s. Yet still pretty thin insulation if that is all there is.

The other option is to finish the room up here and insulate it correctly. If the sidewalls are already high enough in would be pretty easy to put a collar tie across the attic space at each rafter.

The only issue is it is somewhat less effective than just increasing the existing attic thickness as you have increased the volume of the house as far as heating goes to some extent.

Also make sure you put extenders up the eave slots so the soffit vents do not get obstructed with new insulation on the ceiling. I guess you could just spread it over the existing subfloor in the attic as well. Depends on how you want to deal with the storage space.

[mgburg]

The easiest way to see if you needed additional insulation, to begin with, would to have been is to have looked at your roof when there was a decent snowload on it...like back around Christmas time and the time frame right after that. If I remember correctly, you folks got "slammed" with quite a bit of snow during January and February.

You should have been able to compare your roof with any of the neighbors' with similiar lines and slopes. See if you still have snow and at the same thickness/level as they do. If you have more snow and theirs is gone, you're OK to stay. If, however, the snow is gone, you're losing alot of heat up through the attic and at that point, you might want to consider asking an insulation expert what, exactly, you'd need to install.

AAMOF, that's where I'd begin looking first...have a few folks, licensed and bonded, come through and give you an appropriate sense of what you'd really need.

One other simple way of checking if you'd be in the market for, at least, more attic insulation is the "hand test" - and that's just a simple matter of getting up on a decent ladder and placing your hand on the ceiling (that's under the attic area in question) and feeling if it's colder than the room itself...or in the summer time, way warmer than you'd expect. Your comparison would be, then, to place your hand on the wall about a foot or two down from the area you felt on the ceiling. If you don't feel much difference, then don't worry about it...and that's assuming you're satisfied with the way the room feels to you to begin with.

[Skid Row Joe]

Put the insulation on the floor of the attic. I had R45 Johns Manville pure white blown-in on what was R12 when my home was built. You sound like you need a radiant barrier affixed to the bottom of your rafters too.

[barry123400]

Radiant barriers not as common in the north. Much less than five percent I suspect. It is not that they are not a good ideal just not really popular yet in the north.

That said I incorporate them though in new construction.